本文建立了火花点火发动机顶岸间隙、缸套壁面润滑油膜和缸内壁面积碳层处未燃碳氢生成和释放过程的预测模型以及缸内、排气管中未燃碳氢氧化模型，并利用模型预测了发动机排气未燃碳氢量。计算结果表明，本模型的预测结果能较好地与实验结果吻合。 In this paper, a prediction model of unburned hydrocarbon generation and release at the top clearance of spark ignition engine, lubricating oil film on cylinder liner wall and carbon area on the inner wall of cylinder is established, and unburned hydrocarbon oxidation model in cylinder and exhaust pipe is established. The model predicts unburned hydrocarbon emissions from the engine exhaust. The calculation results show that the prediction results of this model are in good agreement with the experimental results.